An air pressure sensor (also called barometer) is an instrument to measure atmospheric pressure. One important application of air pressure sensor is to estimate altitude. FIG. 1 shows the relationship between an elevation above sea level (altitude) in m and an atmospheric pressure (or air pressure). The altitude can be estimated by:H=44307.7*[1−(P/101.325)0.190284]  (Equation 1)
where H is altitude, P is air pressure. In this way, an altitude meter can be made with the air pressure sensor. The altitude meter is widely used in hand-held device, drone, air-craft, and so on.
For example, in a drone application, a noise in such a measurement plays an important role. Generally, the noise of air pressure measurement is about 1.2 Pa (Pascal). It corresponds to an altitude error of about 10 cm. It implies that a drone would fly up-and-down randomly in an altitude range of about 10 cm. This up-and-down behavior would increase the probability of crash especially when a drone is flying low.
For example, a Chinese patent application No. 200610161300.3 discloses an error compensation model and algorithm implementation of a high precision pressure sensor, which is hereby incorporated herein by reference.
A U.S. Pat. No. 7,248,703 B1 discloses systems and methods for adaptive noise cancellation, which is hereby incorporated herein by reference.
U.S. Pat. No. 8,612,810 B2, discloses sensor device provided with a circuit for detection of single or multiple events for generating corresponding interrupt signals, which is hereby incorporated herein by reference.
Therefore, there is a demand in the art that a new solution for processing the sensing signal of a sensor shall be proposed to address at least one of the problems in the prior art.